1. If you travel to or through an owned space station you must pay the owner. Find your cargo in the list next to the space station. Multiply the number of tokens on the space station by the cost of the cargo and pay the owner. If you have no cargo you must pay the owner 10 credits multiplied by the number of tokens on the space station. Do this for all space stations you pass through and the one you stop at.
2. When you stop at a space station you may buy it.
a. If you stop at an unowned space station you may buy it by paying to the bank the number of credits listed under the space station and placing one of your tokens on it.
b. If you stop at an owned space station you may buy it by paying the owner 2x the cost of the space station (including upgrades), placing the same number of tokens on it as the current owner and removing their tokens. (i.e. Denebola with no upgrades would cost 400 credits to buy from the owner, Alphard with 1 upgrade would cost 640 credits to buy from the owner.)
3. If you own all the space stations of a colour set your space stations can not be bought by another player.
4. A space station can be upgraded by paying the bank the number of credits listed under the space station and increasing the number of tokens on it by one. (There is no limit to the number of upgrades per turn.)
5. Space stations can be sold back to the bank. Collect from the bank half the cost of buying the space station and remove all of your tokens from the space station (Space station upgrades have no value when a space station is sold.)